#include<bits/stdc++.h>
using namespace std;
int main(){
    string s,a;
    getline(cin,s);
    getline(cin,a);
    int n,i;
	cin>>n;
	for(i=0;i<n;i++) cout<<a[i];
	for(int j=0;j<s.size();j++) cout<<s[j];
	for(;i<a.size();i++) cout<<a[i];
return 0;
}
/**************************************************************
	Problem: 2020
	User: fzy001
	Language: C++
	Result: Accepted
	Time:15 ms
	Memory:2076 kb
****************************************************************/